Questions tagged [hvac]

(Heating, Ventilating, and Air Conditioning) For questions about installing, repairing, and troubleshooting HVAC systems.

Filter by
Sorted by
Tagged with
1
vote
1answer
664 views

Can I run a C wire from Fan Relay

We've just moved into a new home with an heat only, oil, forced hot air furnace. The current thermostats are very old and we'd like to update them to something like a nest. The furnace is currently ...
1
vote
1answer
425 views

Old AC and Gas Boiler wiring for new thermostat

I need help connecting a new 'C' wire for a Honeywell RTH6500WF thermostat. As you can see the heating is an old boilder with a simple pump to circulate the hot water to the baseboard radiators. The ...
3
votes
1answer
176 views

Can a motorized damper be installed inside existing ductwork?

My HVAC system consists of a fan, furnace, compressor-driven AC, and evaporative cooler. The problem is that there is a large air volume used only by the evaporative cooler that is generating a lot of ...
0
votes
2answers
33 views

Thermostat “fan” function actually using air conditioning

A few months ago, my wife and I started sleeping with our bedroom doors closed to keep out our cat. We would wake up in the middle of the night to find our bedroom was very hot and it felt really hard ...
0
votes
1answer
48 views

Room easy to warm with heater. But difficult to cool with A/C. Is this not insulation related?

I live in an apt building in the 60's. I always notice that the room is always warmer than the outside in the winter time(even with no heating). This stays true in the summer time where it would be 65 ...
0
votes
1answer
7k views

Wiring a Replacement HVAC Blower Motor for an American Standard Heat Pump Air Handler

I undertook what I thought would be a straight forward task.... Needless to say I have run into an issue that I need some help with. The replacement motor is a century 4ka35 motor with the ...
0
votes
4answers
6k views

How to fill / seal in-slab hvac ductwork?

My house is built on a slab. Within the slab are "channels" which act as ducts for the HVAC system. I assume it is partially lined with metal but based on photos from an HVAC-cleaner, it's hard to ...
0
votes
1answer
338 views

Thermostat wires crossed? Fan switch runs condenser fan instead of blower

I have been having this problem for a while and have just not run blower without thermostat calling for heat or AC, system seems to run fine in heat or cool mode, but if I turn on FAN by itself the ...
0
votes
3answers
61 views

I need to pressurize a room and I'm kind of at a loss as to how to do it, hoping someone out there might have some advice

I'm setting up a small packaging operation for edible products for pets. There are certain government standards we have to hit to be able to do this. The actual packaging takes place in a 420 sq ft ...
3
votes
1answer
60 views

Can I draw 240v out of this configuration?

This is how my subpanel looks like. I am looking to install a breaker for an AC unit. 20A. The only caveat is that this has to be 240V. This is a subpanel coming from the main one. There is a breaker ...
1
vote
1answer
34 views

HVAC Air Blowback

Furnace/Blower: Rheem R92PA0851521MSA Dual Zone System (Honeywell TrueZONE HZ311) - Honeywell M847D1004 Actuators Age of system: less than 2 years old including ductwork Ive noticed that if Zone 1 ...
1
vote
2answers
16k views

How can I figure out why the low voltage furnace fuse blows on heat but not cool?

I have a Tempstar Model NTC6100KFG1 gas furnace. Furnace was working fine through the summer blowing the AC. It's been off for a month or two as we've been changing seasons here. When I went to turn ...
0
votes
1answer
892 views

r-410a pressure problem, 285/120 psig

i just installed a new split unit r-410a a/c system. it is running at 285/120 psig. the high side seems way low, should be about 420. the correct orifice is installed. this is a 1.5 ton condenser,...
1
vote
3answers
30k views

Correct Wiring for Furnace Blower Motor

After getting my furnace blower motor replaced, it now runs only in the following scenarios: 1. Mode "Cool" Fan "Auto" 2. Mode "Cool" Fan "On" 3. Mode "Heat" Fan "On" In other words it will not run ...
0
votes
1answer
975 views

How can I add a C-wire to a Venstar T5800 thermostat?

I am trying to replace my existing thermostat. My old thermostat has: Rh, W (coming from the heating unit). Rc, Y, G (coming from the AC unit). On the Venstar T5800, I can map as follows: Rh+Rc -...
0
votes
1answer
141 views

How can I protect an exposed refrigerant pipe outdoors?

I have approx.12 ft. of copper pipe carrying freon laying on top of the ground. Best way to protect it without cutting in two & loosing all freon? (Not enough slack to bury.)
0
votes
2answers
414 views

A/C freezing lines

Issue: evaporator/suction line freezing up in A/C mode. Actions: Replaced fan motor and evaporator coil (no air coming thru old one/beat up petty bad). Relevant Information: Refrigerant Type: R???...
1
vote
3answers
63 views

Water/antifreeze radiator cooled work shop

An additional line of thought. Cooling radiators in summer? I found this having the same concept for cooling. I live in south louisiana, US where 95F is vary common turning tin boxes into a slow ...
0
votes
2answers
137 views

Is my whole-house humidifier installed and working as expected?

I have a Honeywell whole house humidifier model HE240. Its installed on the warm air supply. I thought this would put the humid air into the warm air stream. Instead its blowing air to the cold air ...
1
vote
1answer
30 views

Add common wire to furnace

Trying to add common wire to furnace for smart thermostat. Looking at wiring diagram, it looks like common wire off transformer is blue, switches wire color to white (via wire cap), then back to blue (...
1
vote
3answers
311 views

Undersize AC unit

We just bought/built a new home. We were not given any options regarding the central ac/heat system. We were told simply the system would be sized to fit the house. Soon after moving in it already ...
0
votes
1answer
63 views

What is the fully burdened hourly rate for an HVAC installer? [closed]

While it's pretty simple to get an hourly rate that is paid to an HVAC installer, I have found it more difficult to ascertain what the fully burdened rate is. This is the complete cost a company to ...
1
vote
3answers
1k views

Cooling radiators in summer?

How efficient would it be to use radiators circulating with cold water, to cool house in summer? Wondering if anyone has tried this, and how well it works? I was thinking about H/AC in general, and ...
1
vote
1answer
255 views

C Wire placement in HVAC?

I'm installing a new thermostat and the previous one did not have a C wire connected. Tracing in back to the HVAC, I can't see a C output connection? Based on the wiring diagram (and reading other ...
0
votes
1answer
57 views

Return plenum too big for air handler?

I am currently in the process of changing the air handler and heat pump in my house. I am working with a friend's father who does HVAC for a living. He came over and looked at my HVAC system and gave ...
0
votes
0answers
21 views

HVAC plastic drainage tube snapped off outside

The plastic tube where the condensate drains outside has broken off partly. I would say about 2/3 of it broke off. It still points away from the house a little so shouldn’t get on the wall. Should I ...
1
vote
1answer
239 views

How to handle unattached ground wires in boiler fusebox/control panel (sub-panel?)?

I don't have enough of an understanding of HVAC to know if the pictured boiler fuse box is considered a control panel or a sub-panel - but some wiring issues there lead me to needing to understand ...
0
votes
2answers
2k views

Indoor blower fan turns on and off intermittently in 10-15 min increments when system is off

Bit of background: The furnace blower originally did not not turn off at all (or if it did, very rarely did so), even when set temps were reached or when the system was off (fan setting is set to auto,...
2
votes
1answer
42 views

Adding ventilation to an older outbuilding

I have a large to me storage building that I am trying to convert into a garage/workshop. I don't have the time/money/inclination to tear the whole thing down and start anew so I am trying to make ...
0
votes
0answers
19 views

Hvac fuse blowing on furnace board

A 5 amp fuse keeps popping at startup on my tempstar furnace,had a problem a couple weeks ago and put fuse in and worked fine.Now it blows instantly.
0
votes
2answers
26 views

Placement of a package unit heat pump for my shop

I was wondering if I would benefit by locating my 3 ton package unit heat pump closer to the load center. The ducting would be my only interference with it closer to the load center. The unit would ...
1
vote
1answer
59 views

Why the noises in the new furnace?

A company installed a new HVAC system 2 weeks ago. The furnace model was new: 58TNOA110C21–20. I initially ordered 58CVA110-20 but they said it will be out of market soon in August. So they installed ...
1
vote
1answer
221 views

How should I jumper the transformer to use a thermostat with my heat pump?

I am hooking up an aftermarket blower motor on my Trane XL 1400 AC/heat pump. I have a black, blue, red & white wires coming out of the new motor. I am bypassing the circuit board so I am ...
3
votes
3answers
29k views

Better to run air conditioner fan on high or low speed?

In my apartment, I have two window air conditioning units. Both have different settings for the fan speed: one has two speed options and the other has three. Both have the design that the room ...
0
votes
0answers
42 views

Split unit Air Conditioner replace compressor single to three phase

I have a 3-ton split AC "single-phase compressor" was working perfectly until I moved it to another location, some oil spilled from the suction pipe during the transportation so when I installed it in ...
0
votes
1answer
184 views

Oil furnace fan won't shut off when “heat” plug is connected to control board

I was changing my thermostat and I attempted to make the swap live without turning power off. When I connected new thermostat, the fan kept running. Ruled out bad thermostat and wire short by ...
1
vote
1answer
125 views

Thermostat C Wire (Possibly Unconnected)

I purchased a Honeywell RTH6500 Wifi Thermostat, which requires a C wire. My old thermostat showed a connected blue C wire. However, it was battery-powered. If I removed the battery, the thermostat ...
1
vote
2answers
2k views

Why does my electric furnace sometimes blow cold air?

I have an electric furnace that blow cold air sometimes. I replaced the thermostat and that did not fix it. The fan blows fine. If I shut if off for a few minutes and then try again, about half the ...
0
votes
1answer
192 views

Connect Wifi Thermostat to Goodman GMP050-3?

I'm trying to connect up a wifi thermostat to Goodman furnace, specifically the GMP050-3. I've done some reading on this but I'm still not quite sure how to go about it. Specifically, I'm not sure ...
26
votes
2answers
3k views

What is an air conditioner compressor hard start kit and how does it work?

My air conditioner compressor wasn't functioning properly recently. The compressor wouldn't start when the start relay energized. A HVAC technician diagnosed the problem nebulously as "It needs a hard ...
0
votes
2answers
2k views

What size start capacitor should I buy for my refrigerator compressor?

What size (in horsepower) 3-in-1 start capacitor should i buy for my fridge compressor? I have an LG LRSC26922TT from 2003. The compressor isnt staying on due to (i think the PTC hooked to the ...
0
votes
1answer
33 views

Trane Furnace Fan Works, But Heater Won't Run

As stated, my heat isn't coming on. When this started: Everything has been all fine and dandy all winter. The other day I ran the fan only for a few hours without the heat. After this, my heat ...
0
votes
3answers
213 views

How do I bleed a noisy radiant heat system?

I have a gas fueled (converted from oil just a few years ago) boiler in my basement with an integrated tank-less water heating system for the showers/taps/etc. The output is three zones as shown in ...
0
votes
1answer
36 views

AC unit dripping onto crawl space vapor barrier

I just bought a house whose crawlspace looks like it was partially converted to being sealed off. Basically, they put down a vapor barrier and closed off the vents, but didn't finish the job. On top ...
1
vote
1answer
513 views

Is my Nest thermostat wired correctly?

I've been having issues like the heat pump not heating. Now that it's hot outside, my A/C isn't working. Can someone tell me if my Nest thermostat is even wired correctly? If it helps any, here is ...
2
votes
1answer
530 views

New Thermostat installed but compressor comes on immediately

I have a new Insteon Thermostat that I'm using to replace my prior Honeywell t-stat. This is installed to a relatively new HVAC system (both AC and Heat) that DOES have a "c" wire. I've attached the ...
1
vote
1answer
46 views

Window AC fan drip pan full

My AC started to blow out pretty lukewarm air recently, as well as make watery sounds while running. I realized the filter was dirty, and I cleaned the coils, replaced the filter and removed lots of ...
0
votes
1answer
35 views

How to retrofit existing kitchen exhaust fan

I'm remodeling a kitchen that is circa 1940's. In the kitchen is an exhaust fan that sits inside a 3.25x10 duct. I would like to keep an exhaust fan in this location and re-use the existing duct, ...
2
votes
1answer
55 views

Another “How do I add ”c" wire to boiler for Nest

I have tried searching this forum and others, but I could not find anyone with a situation like mine. I thought it better to ask here, rather than damage something. I have a Lennox wall mounted ...
1
vote
1answer
101 views

Which terminal should I connect it to for a “C” wire on an american standard AM4A0A30

I'm trying to connect a 3rd gen Nest thermostat. I have a 2 zoned heat and 1 zone AC. The zone with this thermostat has a boiler wired Rw, W1 and HVAC wired Rc, G, Y1. It's summer so I'm only using ...